The wireless telecommunications industry has experienced phenomenal growth in recent years, particularly in the area of cellular telephone communications. This growth has led to a saturation of existing base station capacity in some areas. The growth in usage has also resulted in a shift in typical calling patterns of mobile telephone users. Initially, cellular telephones were primarily used to maintain communications by individuals whose jobs required mobility and those who were on-call during times that they were away from an office. Thus, the primary usage pattern was establishing a connection between a mobile cellular telephone and a fixed office within the Public Switched Telephone Network (PSTN). As cellular telephones have became ubiquitous, and particularly as ever-increasing sophistication has evolved the cellular telephone from a purely communications device to a multi-function mobile terminal, many people have adopted the mobile terminal as their primary vehicle for telecommunications. These people are as likely to use their mobile terminal to dial another mobile terminal as to dial a telephone within the PSTN. Hence, mobile-to-mobile communications comprise a large and increasing fraction of the cellular telephony bandwidth, bypassing the PSTN altogether.
To accommodate the burgeoning volume and emerging patterns of mobile-to-mobile wireless communications, a need exists for communications techniques that make maximum, efficient use of existing equipment bandwidth, within the confines of the existing infrastructure.
In one embodiment, the present invention comprises a wide area wireless mobile communications system with inter-base station communications capability. A Mobile Switching Center (MSC) having a serial port interface is operatively connected to a Public Switched Telephone Network (PSTN). A serial communications bus, such as a T1 or E1 line, connects the MSC to a plurality of base stations via a first serial port having a first interconnection order at each base station. Each base station also connects to the serial communications bus via a second serial port having a second, opposite interconnection order. In a first communications mode, the MSC communicates with each base station over the serial communications bus through the base station""s first serial port. In a second communications mode, each base station can communicate with any other base station over the serial communications bus, without intervention of the MSC, with one base station utilizing the first serial port, and the other base station utilizing the second serial port.
In another embodiment, the present invention comprises a limited-area wireless mobile communications system with inter-radio head communications capability. A serial communications bus, such as a T1 or E1 line, connects a Control Radio Interface (CRI) to a plurality of radio heads via a first serial port having a first interconnection order at each radio head. In a first communications mode, the CRI communicates with each radio head across the serial communications bus through the first serial port of each radio head. Each radio head also connects to the serial communications bus via a second serial port having a second interconnection order, opposite that of the first serial port. In a second communications mode, each radio head can communicate with any other radio head over the serial communications bus, without intervention of the CRI, with one radio head utilizing the first serial port, and the other radio head utilizing the second serial port.